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Constitutive modelling of mechanically induced martensitic transformations: Prediction of transformation surfaces

Daniel de Bortoli (Department of Mechanical Engineering, University of Porto, Porto, Portugal and Zienkiewicz Centre for Computational Engineering, Swansea University, Swansea, UK)
Fauzan Adziman (Department of Engineering Science, University of Oxford, Oxford, UK and Zienkiewicz Centre for Computational Engineering, Swansea University, Swansea, UK)
Eduardo A. de Souza Neto (Zienkiewicz Centre for Computational Engineering, Swansea University, Swansea, UK)
Francisco M. Andrade Pires (Department of Mechanical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal)

Engineering Computations

ISSN: 0264-4401

Article publication date: 16 April 2018

306

Abstract

Purpose

The purpose of this work is to apply a recently proposed constitutive model for mechanically induced martensitic transformations to the prediction of transformation loci. Additionally, this study aims to elucidate if a stress-assisted criterion can account for transformations in the so-called strain-induced regime.

Design/methodology/approach

The model is derived by generalising the stress-based criterion of Patel and Cohen (1953), relying on lattice information obtained using the Phenomenological Theory of Martensite Crystallography. Transformation multipliers (cf. plastic multipliers) are introduced, from which the martensite volume fraction evolution ensues. The associated transformation functions provide a variant selection mechanism. Austenite plasticity follows a classical single crystal formulation, to account for transformations in the strain-induced regime. The resulting model is incorporated into a fully implicit RVE-based computational homogenisation finite element code.

Findings

Results show good agreement with experimental data for a meta-stable austenitic stainless steel. In particular, the transformation locus is well reproduced, even in a material with considerable slip plasticity at the martensite onset, corroborating the hypothesis that an energy-based criterion can account for transformations in both stress-assisted and strain-induced regimes.

Originality/value

A recently developed constitutive model for mechanically induced martensitic transformations is further assessed and validated. Its formulation is fundamentally based on a physical metallurgical mechanism and derived in a thermodynamically consistent way, inheriting a consistent mechanical dissipation. This model draws on a reduced number of phenomenological elements and is a step towards the fully predictive modelling of materials that exhibit such phenomena.

Keywords

Acknowledgements

The first and second authors gratefully acknowledge the Zienkiewicz Research Scholarships provided by Swansea University’s College of Engineering during the course of much of this work.

Citation

de Bortoli, D., Adziman, F., de Souza Neto, E.A. and Pires, F.M.A. (2018), "Constitutive modelling of mechanically induced martensitic transformations: Prediction of transformation surfaces", Engineering Computations, Vol. 35 No. 2, pp. 772-799. https://doi.org/10.1108/EC-03-2017-0087

Publisher

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Emerald Publishing Limited

Copyright © 2018, Emerald Publishing Limited

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